The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Internal combustion engines combust an air/fuel mixture to generate torque and propel a vehicle. Combustion of the air/fuel mixture produces exhaust that is expelled from an engine to an exhaust system. Exhaust systems associated with soot producing internal combustion engines, such as diesel-type engines or direct injection engines, include a treatment system that treats the exhaust before the exhaust is expelled from the exhaust system.
The treatment system may include one or more injectors that inject a fluid into the exhaust system. For example, exhaust systems having an oxidation catalyst (OC) may include a hydrocarbon (HC) injector that injects a HC fluid (e.g., fuel) upstream of the OC. Once the OC reaches a predetermined temperature, injected HC may be combusted by the OC. Exhaust systems having a selective catalytic reduction (SCR) catalyst generally include a dosing agent injector that injects a dosing fluid (e.g., urea) upstream of the SCR catalyst. The SCR catalyst selectively absorbs the dosing fluid and reduces nitrogen oxides (NOx) passing the SCR catalyst.